The rare coordinated attempts on the lives of Israeli diplomatic representatives came a month after the latest assassination of an Iranian nuclear scientist and were set against an escalating war of words between Israel and Iran over a possible Israeli strike on Iranian nuclear facilities. The attempted attacks also coincided with the fourth anniversary of the assassination of Imad Mughniyeh, a leader of Hezbollah, a militant Shiite Lebanese group backed by Iran.

Tehran has vowed revenge for the killing of its scientists, which it has blamed on Israel, and Hezbollah has vowed to avenge the slaying of its leader, considered a mastermind of some of the group’s deadliest attacks.

There was no immediate claim of responsibility for the incidents, but Israeli officials said they appeared to have been directed by Iran, and they warned that if the Islamic republic becomes a nuclear power, it could provide greater protection for militant groups that would be emboldened by its support. Iran denied responsibility for the bombing attempts, calling them an Israeli provocation.

Israeli Prime Minister Benjamin Netanyahu cited places where he said attacks on Israelis and Jews had recently been foiled, including Thailand and Azerbaijan, and he accused Tehran of orchestrating Monday’s plots, calling Iran “the greatest exporter of terrorism in the world.”

“In all these cases, the elements behind the attacks were Iran and its proxy, Hezbollah,” Netanyahu said. “We will continue to act with a strong hand, systematically and patiently, against international terrorism, whose source is Iran.”

In Washington, White House spokesman Jay Carney was more cautious, saying that the United States had “no information yet on who is responsible for these attacks” and adding, “We have not made a judgement yet.”

Secretary of State Hillary Rodham Clinton issued a condemnation of the bombing incidents, calling them acts of terrorism, but she avoided any accusation of responsibility.

The United States is leading a global push for sanctions that it hopes will force Iran to suspend its uranium-enrichment program, while urging caution on Israel, which is weighing a preemptive strike against Iranian nuclear facilities. The United States, Israel and others suspect that Iran is trying to acquire the material and technology needed to build a nuclear weapon. Iran, however, says its nuclear program is aimed only at producing energy and medical isotopes.

‘Psychological warfare’

Iran’s ambassador to India, Mehdi Nebizadeh, said Iran played no role in Monday’s attack in New Delhi.

The Iranian Foreign Ministry spokesman, Ramin Mehmanparast, said Israel was behind the bombing incidents, which he said were intended to “tarnish Iran’s friendly ties with the host countries” and wage “psychological warfare against Iran,” according to the state-run Islamic Republic News Agency. “Iran condemns terrorism,” the spokesman added.

In New Delhi, the wife of a member of Israel’s defense mission to India and her driver, along with two people in a nearby car, were wounded when a magnetic bomb was slapped onto her car by a passing motorcyclist as she headed to pick up her children from the American Embassy School, according to accounts by Indian and Israeli officials. The woman, Tal Yehoshua-Koren, works at the Israeli Embassy and was hospitalized with moderate injuries, Israeli officials said.

The attack, a few hundred yards from the prime minister’s residence, bore eerie similarities to the Jan. 11 killing of Iranian nuclear chemist Mostafa Ahmadi-Roshan, a 32-year-old deputy head of procurement at the Natanz enrichment facility. The scientist was killed in an explosion after an unknown assailant on a motorcycle slapped a magnetic bomb on his car as he commuted to work.

Iran has openly threatened retaliation for the recent killings of its nuclear scientists and has blamed the assassinations on Israel and the United States. Clinton has categorically denied any U.S. involvement; Israeli officials have refused to comment.

At about the same time as the attack in New Delhi, officials said, a grenade was found taped to the bottom of the car of a driver for the Israeli Embassy in Tbilisi, capital of the former Soviet republic of Georgia. It was safely defused.

Already on high alert

Netanyahu offered no specific evidence for his claim that Iran was responsible for Monday’s incidents. But Israel had put its foreign missions on high alert in recent days because of the anniversary of the death of Mughniyeh, the Hezbollah mastermind, who was killed in Damascus, Syria, on Feb. 12, 2008, when a bomb planted in a headrest in his car was detonated.

Yuli Edelstein, the Israeli minister of public diplomacy, said Hezbollah and other militant groups sponsored by Iran would gain additional protection if Tehran were allowed to obtain a nuclear bomb.

“If the umbrella is based on a strategic weapon — a nuclear weapon — then it will be very difficult to penetrate that umbrella,” he told Israel Radio. “As terrorist groups, it will be very comfortable for them to be under that umbrella.”

But Shlomo Brom, an analyst at the Institute for National Security Studies at Tel Aviv University, drew a distinction between Monday’s incidents and the standoff over Iran’s nuclear program. He said the bombing attempts were part of a shadow war that has been going on for years between Israel and Iran and the militant groups it supports.

“This is part of the covert war between the two sides,” Brom said. “The secret war is a separate playing field and is not something new. As long as both sides want to keep it there, it won’t affect the general tension.”

Denyer reported from New Delhi. Correspondents Thomas Erdbrink in Tehran and Kathy Lally in Moscow contributed to this report.

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